With initial news of B1, 15 conference participants remaining in Singapore were contacted to find out about their health status. Four people reported being unwell with fever, respiratory symptoms, or both and were tested for SARS-CoV-2; two individuals (B4 and B5) tested positive for the virus. The third local case (B6) was identified via activity mapping to have attended the conference and had subsequent interactions with company staff. 153 close contacts were placed under quarantine. Hotel staff were told to monitor their health status, and none reported being unwell during the conference or subsequently. 13 secondary cases of COVID-19 were reported among family members of B1 in Malaysia and contacts of B7 in France.